List:General Discussion« Previous MessageNext Message »
From:Johan De Meersman Date:March 31 2011 6:20pm
Subject:Re: A common request
View as plain text  

----- Original Message -----
> From: "mos" <mos99@stripped>
> 
> The IN() clause is very inefficient because MySQL will NOT use the
> index.
> It will have to traverse the entire table looking for these values.

Has that still not been remedied ?

> It will get the information from the index and not have to access the
> record data from disk. If the index is stored in memory, then it
> won't have to go to disk (unless you also have a sort). That is why the query
> cache is so important.

Indices don't go in the query cache, strictly speaking, they go in the MyISAM index cache
or in the InnoDB pool.


-- 
Bier met grenadyn
Is als mosterd by den wyn
Sy die't drinkt, is eene kwezel
Hy die't drinkt, is ras een ezel
Thread
A common requestGregory Magarshak29 Mar
  • Re: A common requestPeter Brawley29 Mar
    • Re: A common requestGregory Magarshak29 Mar
      • Re: A common requestPeter Brawley29 Mar
        • Re: A common requestGregory Magarshak31 Mar
          • Re: A common requestGregory Magarshak31 Mar
            • Re: A common requestJohan De Meersman31 Mar
          • Re: A common requestmos31 Mar
            • Re: A common requestJohan De Meersman31 Mar
            • Re: A common requestmos31 Mar
              • Re: A common requestWm Mussatto31 Mar
  • Re: A common requestSander de Bruijne29 Mar